1. Related Application
This application claims priority from Japanese Patent Application No. 2001-394990 which is incorporated herein by reference.
2. Field of the Invention
The present invention relates to a rotating connector for transmitting electrical signals and/or optical signals between two members which rotate relative to each other.
3. Description of Related Art
A rotating connector is provided, for example, in a steering system of an automobile to electrically or optically connect an electronic circuit provided on a vehicle-body side and an electrical or electronic apparatus incorporated into a steering wheel to transmit electrical signals and/or optical signals and supply electric power.
In the rotating connector, a rotating case which is attached to a steering shaft and a stationary case which is attached to a steering column (vehicle body) are connected together in a manner that they can rotate relative to each other. Inside the connected cases is formed an annular space, in which a flat cable for transmitting electrical signals and/or optical signals is held.
As one type of the rotating connector, what is called a roller U-turn SRC (steering roll connector) is known, for example, from Japanese Unexamined Patent Publication No. 2001-112156 or U.S. Pat. No. 6,409,527B1. In the roller U-turn SRC, a ring-shaped member with a plurality of rollers is held in the above-mentioned annular space in a manner that it can move in the circumferential direction, and, for example, two flat cables are held in the annular space in a manner that they are wound like a swirl, each being U-turned at about the middle thereof with the help of one of the rollers, and fixed to the rotating case at one end and the stationary case at the other end.
The rollers are supported by the ring-shaped member which rotates in the annular space. The rollers guide the flat cables, which are tightened or loosened as the rotating case rotates, and help the flat cables U-turn.
When a rotating connector having flat cables U-turned at about the middle thereof as mentioned above is left in a high-temperature environment of, for example, about 85° C. or higher for two hours, the flat cables tend to remain curved. This tends to cause abnormal noise called flap noise, next time the rotating connector rotates. The thicker the flat cables, the more they remain curved.